This invention relates to apparatus for and a method of batch drying various crops. This invention is particularly concerned with batch drying specialty crops, such as peanuts, rice and edible beans.
In the case of drying peanuts, special problems are presented. First, it will be recognized that peanuts are contained within a shell and the shell and the peanuts therein must be dried. Further, with the peanuts in the shell, the flowability of the peanuts is markedly less than the flowability of other crops, such as shelled corn, soybeans, milo, and the like. Presently, peanuts are dried in wagons brought to a drying facility with the peanuts remaining in the wagons while they are dried. The drying wagons have a perforate drying floor on which the wet peanuts are loaded and a plenum beneath the drying floor. A fan/heater is adapted to be connected to the plenum for introducing heated air into the plenum such that the heated air will be forced upwardly though the perforate floor of the wagon and into the peanuts loaded in the wagon. After the peanuts are dried, the peanuts are dumped from the wagons for storage.
Batch grain drying systems, such as are shown in U.S. Pat. Nos. 3,479,748 and 3,943,636 are known in which wet grain to be dried is conveyed to the top of a drying bin and discharged into a center opening in the peak of the bin roof. As best shown in U.S. Pat. No. 3,943,636, a sloped, perforated drying floor is provided in the upper portion of the bin beneath the bin roof. As the grain is discharged into the bin at the top thereof, the grain flows down sloped drying floor and forms a uniform layer thereon. A heater fan blows heated air into the bin below the sloped drying floor and the heated air, under pressure flows through the perforated drying floor and through the layer of grain supported thereon to dry the grain. Trap doors are provided around the lower outer margins of the sloped drying floor such that when the trap doors are opened, the batch of grain on the sloped drying floor is discharged by gravity via the trap doors into the bin below the drying floor. The lower portion of the bin has a raised, horizontal floor made of perforated floor members. Air from another blower is forced beneath the horizontal floor to pass through the floor and into the grain supported thereon to cool and further condition the grain dried on the sloped drying floor.
Other drying processes, such as shown in U.S. Pat. No. 2,469,424, are known in which wet grain to be dried is loaded into a hopper at the top of a tower. The wet grain is continuously discharged from the hopper onto a first sloped drying floor which has a slope approximately of the angle of repose of the wet grain being dried. The grain flows continuously down the first drying floor and is continuously discharged from openings around the outer margins of the first drying floor and is received on the upper reaches of a second drying floor therebelow. The second drying floor slopes inwardly and downwardly toward the center of the tower and the grain is received on the upwardly facing surface of this second or inverted drying floor. The grain flows down the second drying floor and is discharged from a center bottom opening onto the outer surface a third sloped drying floor. The grain then continuously flows by gravity down the outer surface of this third drying floor and then onto the inner surface of a fourth drying floor therebelow. The fourth drying floor is an inverted sloped floor and the grain is received on the inner face thereof. The slope of the third and the fourth drying floors are less steep than the slope of the first and second drying floors because the partially dried grain flowing down the third and fourth drying floors has a somewhat different angle of repose than the wet grain flowing down the first and second drying floors. This continuous dryer has a partition which divides the third and fourth drying floors. The space below the partition is in communication with a cold air duct which draws a partial vacuum within the space below the partition and above the fourth drying floor so that ambient air from the bottom portion of the dryer is drawn through the air previous fourth drying floor and through the grain flowing down the inner face thereof.
However, there has been a long-standing need to batch dry specialty crops, such as peanuts, in a manner that does not require the use of wagons during the drying process.